hidserv*seen_value and hidserv*cells_value should be BIGINT

Right now we have:

hidserv_rend_relayed_cells_value    DOUBLE PRECISION,
hidserv_rend_v3_relayed_cells_value DOUBLE PRECISION,
hidserv_dir_onions_seen_value       DOUBLE PRECISION,
hidserv_dir_v3_onions_seen_value    DOUBLE PRECISION,

However, it's a bit weird to have a DOUBLE numeric type for something that should be some integer really. And, in fact, that's what the spec says as well (emphasis mine):

third, the result of the previous obfuscation steps is truncated to the next smaller *integer* and included as 'NUM'

(Note: this needs a metrics-lib patch)